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NDMP Backup

Shaun_Taylor
Level 5
Certified

I've occasionally noticed a few lines in detailed job statuses of our NDMP backups of EMC NAS shares that say something similar to "Unable to open <file> to read. Stale handle.". However, the job still finishes successfully with a status 0.

Has anyone encountered this before, or know what it means / what the cause could be?

9 REPLIES 9

Maurice_Byrd
Level 4

A stale handle occurs when there is an open reference to a file that is moved, deleted, etc. 

Here's a link to a thread for a similar issue and resolution.

Shaun_Taylor
Level 5
Certified

Thanks Maurice. So just to confirm - if a file exists when a backup job starts, but has been deleted by the time the file is going to be backed up, this would result in a stale handle message?

Andy_Welburn
Level 6

How do NDMP backups actually work on EMC storage devices? (or what exactly are you backing up?)

 

We used to do NDMP backups of NetApp filers. Now as far as I remember these used to create a snapshot at backup time & then used these to backup from so there's no issue with backing up files that could 'disappear' or change between start & finish. Having said that, we mainly backed up from a scheduled snapshot anyway, but you get the picture .....

Shaun_Taylor
Level 5
Certified

I believe it works in the same way that you described Andy - however, I'll have to confirm this. As you point out, if snapshots are being used then I'm not sure what could be the cause.

Andy_Welburn
Level 6

The link Maurice directed you to shows the same symptoms to a point but then the backup actually fails & most of the Google hits (that I can read) support the fact that this can happen for the reasons Maurice stated.

Do not have access to EMC support so maybe the document mentioned in the last post has more info if you can gain access to it? (EMC181207)

Shaun_Taylor
Level 5
Certified

Thanks for the help guys.

I've done a bit of research and it looks like using SnapSure snapshots for NDMP backups is optional. I'll look into this further as soon as possible and post what I find.

Maurice_Byrd
Level 4

Shaun & Andy,

You're right that NBU creates a snapshot before the backup. It's been a while since I've seen this error. Probably a couple of years since we upgraded our NetApp filers.  I have three different NDMP backup jobs configured for three different filers.  They each use a different snapshot method.

  1. A NetBackup 3-way NDMP
  2. NBU targets a path and captures NetApp snaps via NDMP
  3. NBU targets a path and captures snaps created by Snap Manager for Exchange via NDMP

Since I don't manage the SAN or Exchange, I like targeting the filers directly to capture the data. If a restore is required, I just put the snapshots back where they came from and let the respective admins work with the customer.

I'm not familiar with SnapSure but if it works like Snap Manager it shouldn't be too hard to setup.  

 

 

 

ontherocks
Level 6
Partner Accredited Certified

http://www.symantec.com/business/support/index?page=content&id=TECH31885

 

NDMP policy should specify snapshot-based backup
To make sure that the backup is based on data that is transactionally consistent,
the following should be the first entry in the NetBackup policy Backup
Selections list:
set snapsure=yes
The Celerra Server creates a snapshot and the backup is created from the
snapshot. The snapshot is managed by the EMC Celerra, not by NetBackup.

 

 

 

Shaun_Taylor
Level 5
Certified

That's similar to what I've found so far as well - when I get a chance later this week I'll confirm with EMC if there is extra configuration required (or any other considerations).